gO HORTICULTURE BY IRRIGATION. 



RASPBERRY SAW FLY (Selandria Rubi.) 



The larva of the saw fly are injurious to the rose, the plum and the 

 raspberry. The greenish slugs destroy the pulpy portion of the leaf, 

 feeding on its underside, and are generally present in numbers sufficiently 

 numerous so that the foliage looks as if scorched by fire. One or two 

 applications of the wet mixture of hellebore will be found effective in 

 destroying them. 



We follow Professor Cassiday's paper with a few comments on 

 FRUIT TREE BLIGHT. 



As there is neither a certain known remedy nor preventive for 

 apple and pear tree blight, no attempt will be made to discuss the disease 

 here. Probably the best safeguard that can be adopted is to plant 

 orchards on high, well drained sites, and in soils rich enough to induce 

 a thrifty annual growth. If trees can be protected from sudden extremes 

 of heat and cold and, in fact, from all immoderate or unseasonable 

 changes in temperature, so much the better. It may be stated on general 

 principles that whatever tends to impair the vitality of a tree, renders it 

 more liable to disease of any kind. 



While scientific investigations disclose the presence of bacteria in 

 cases of tree blight, it is by no means a settled question that these (micro- 

 coccus amylovorus) are the true cause. Professors Arthur, of New York, 

 and Burrill, of Illinois, maintain, I believe, that they are, while others 

 are inclined to the view that bacteria are rather an accompaniment or 

 result of a diseased condition. 



Sections like Colorado are likely to be much more exempt from the 

 trouble than many portions of the East. 



